This Offenhauser carb adapter will work on their flathead 4 brl intake manifold (also Y-block Ford and other apps) to put on either a Carter AFB, Edelbrock Performer or Holley std bore 4 brl. ( AFB or Edelbrock won’t work on 48 and earlier engines because of the water outlets). The manifold base measurement is 3 & 7/8″ X 3 & 3/4″. It is prox 1/2″ thick.
Please note that the 90 degree drill are made to order and will take two weeks to process from date of order.